1

Imagine that all White pieces are in their initial position and Black only has their king on e8. What is the smallest number of moves needed for White to give checkmate?

2
4

There seem to be many ways to mate in 6. That is the best I found. Here is one.

[FEN "4k3/8/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1"]

1.e4 Ke7 2.Qg4 Kd6 3.Qg7 Kc5 4.d4+ Kb4 5.Bd2+ Ka4 6.b3#
6
  • 2
    I like the fact that the queen isn’t even doing anything…
    – fartgeek
    Sep 15 at 12:12
  • 1
    @fartgeek: The queen may not be giving checks, but she is surely doing quite a lot on g7 (most importantly, the queen forces the king to run away to the queenside, blocks the king from fleeing to the 7th rank, and guards the pawn on d4).
    – Kevin
    Sep 15 at 19:45
  • Just for fun, I first interpreted the question as "White serial mover" (I'm a problemist :-). The answer then is almost unique: 1.e3,4 2.Qf3 3.Qf6 4.Bb5# Sep 16 at 9:27
  • Thank you for all your contributions. What seems to be ignored, though, is my original restriction/demand that black gives his/her best play. Sep 16 at 12:00
  • @KaiKäkelä The line I provided is stockfish 14 best play for both sides at 100 ply. This appears to be mate in 6. There are many moves that result in mate in 6. To me, all those moves are equal. Therefore there is no better play than what I provided Sep 16 at 12:08

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